This film takes a fascinating idea and explores it fully through all the twists and turns. You really don't know what will happen as the story grows. If you want to see a heartfelt comedy that's definitely NOT a standard rom-com, this is worth a watch.
Seriously, almost every rom-com since Shakespeare is about mistaken identities. (Amelie, When Harry Met Sally, and Annie Hall are exceptions.) Although that can be hilarious, it's been used for hundreds of years. Here's something different.
Review of Babysplitters
